Method and apparatus for driving motor and appliance

Abstract

A method and apparatus for driving motor and appliance. When a rotor of a motor rotates, a current angle of the rotor is detected at a current moment by using a Hall sensor; a back electromotive force and a phase current of the motor is detected at the current moment; a target torque coefficient is detected by using a relational model for a back electromotive force and a torque coefficient according to the back electromotive force; a current torque coefficient is detected by using a relational model for a phase current and a torque coefficient according to the detected phase current; and a compensation angle is detected according to a rotor angle compensation model and the current angle is compensated by using the compensation angle, to obtain an adjustment angle; and power supply to the motor is adjusted according to the adjustment angle by using a field orientation technology.

The invention claimed is: 
     
       1. A motor driving method, wherein the motor driving method comprises:
 when a rotor of a motor rotates, detecting a current angle of the rotor at a current moment by using a Hall sensor, detecting a back electromotive force of the motor at the current moment, and detecting a phase current of the motor at the current moment; 
 determining a target torque coefficient by using a relational model for a back electromotive force and a torque coefficient according to the back electromotive force; 
 determining a current torque coefficient by using a relational model for a phase current and a torque coefficient according to the detected phase current; 
 and determining a compensation angle according to a rotor angle compensation model if a difference between the current torque coefficient and the target torque coefficient is outside a first error range; and 
 compensating the current angle by using the compensation angle, to obtain an adjustment angle; and adjusting power supply to the motor according to the adjustment angle by using a field orientation technology. 
 
     
     
       2. The motor driving method according to  claim 1 , wherein the motor driving method further comprises:
 when the rotor of the motor rotates, detecting a rotational speed of the rotor at the current moment by using the Hall sensor; and 
 the step of determining a target torque coefficient by using a relational model for a back electromotive force and a torque coefficient according to the back electromotive force is specifically: 
 determining the target torque coefficient according to the back electromotive force and the rotational speed by using a first torque coefficient model; wherein 
 the first torque coefficient model is 
 
       
         
           
             
               
                 
                   K 
                   T 
                 
                 = 
                 
                   
                     3 
                     2 
                   
                   × 
                   
                     E 
                     n 
                   
                   × 
                   
                     60 
                     
                       2 
                       ⁢ 
                       π 
                     
                   
                 
               
               , 
             
           
         
       
       wherein K T  is the target torque coefficient, E is a peak value of the back electromotive force, and n is the rotational speed of the rotor. 
     
     
       3. The motor driving method according to  claim 1 , wherein the relational model for a phase current and a torque coefficient is 
       
         
           
             
               
                 
                   K 
                   T 
                   ′ 
                 
                 = 
                 
                   T 
                   I 
                 
               
               , 
             
           
         
       
       K T   ′  is the current torque coefficient, T is a preloaded load torque, and I is a peak value of the phase current of the motor. 
     
     
       4. The motor driving method according to  claim 3 , wherein the step of determining a compensation angle according to a rotor angle compensation model if a difference between the current torque coefficient and the target torque coefficient is outside a first error range comprises:
 determining whether the current torque coefficient and the target torque coefficient meet a torque coefficient error model, wherein the torque coefficient error model is 
 
       
         
           
             
               
                 
                   
                     
                       K 
                       T 
                       ′ 
                     
                     - 
                     
                       K 
                       T 
                     
                   
                   
                     K 
                     T 
                   
                 
                 | 
                 
                   ≤ 
                   ɛ 
                 
               
               , 
             
           
         
       
       and ε is determined according to the first error range; and
 if the current torque coefficient and the target torque coefficient meet the torque coefficient error model, using the current angle as the adjustment angle; or if the current torque coefficient and the target torque coefficient do not meet the torque coefficient error model, determining the compensation angle according to the rotor angle compensation model. 
 
     
     
       5. The motor driving method according to  claim 1 , wherein the step of determining a compensation angle according to a rotor angle compensation model specifically comprises:
 determining whether a difference between the current torque coefficient and the target torque coefficient is within a second error range; and 
 if the difference is outside the second error range, determining the compensation angle θ i  by using a first rotor angle compensation model, wherein the first rotor angle compensation model is θ i =2 i ×Δ, θ i  is an angle for the i th  compensation, i is greater than 1, and Δ is a unit angle; or 
 if the difference is within the second error range, determining the compensation angle θ i  by using a second rotor angle compensation model, wherein the second rotor angle compensation model is θ i =1/2×(|θ i-1 −θ i-2 |), θ i  is an angle for the i th  compensation, θ i-1  is an angle for the (i−1) th  compensation, and θ i-2  is an angle for the (i−2) th  compensation. 
 
     
     
       6. A motor driving apparatus, wherein the motor driving apparatus comprises an angle detection module, a back electromotive force detection module, a phase current detection module, and an adjustment module; wherein
 the angle detection module is configured to: when a rotor of a motor rotates, detect a current angle of the rotor at a current moment by using a Hall sensor; 
 the back electromotive force detection module is configured to: when the rotor of the motor rotates, detect a back electromotive force of the motor at the current moment; 
 the phase current detection module is configured to: when the rotor of the motor rotates, detect a phase current of the motor at the current moment; 
 the adjustment module comprises a target torque coefficient determining unit, a current torque coefficient determining unit, a compensation angle determining unit, an adjustment angle obtaining unit, and a power supply adjustment unit; 
 the target torque coefficient determining unit is configured to determine a target torque coefficient by using a relational model for a back electromotive force and a torque coefficient according to the back electromotive force detected by the back electromotive force detection module; 
 the current torque coefficient determining unit is configured to determine a current torque coefficient by using a relational model for a phase current and a torque coefficient according to the phase current detected by the phase current detection module; 
 the compensation angle determining unit is configured to determine a compensation angle according to a rotor angle compensation model if a difference between the current torque coefficient and the target torque coefficient is outside a first error range; 
 the adjustment angle obtaining unit is configured to compensate, by using the compensation angle, the current angle detected by the angle detection module, to obtain an adjustment angle; and 
 the power supply adjustment unit is configured to adjust power supply to the motor according to the adjustment angle by using a field orientation technology. 
 
     
     
       7. The motor driving apparatus according to  claim 6 , wherein the motor driving apparatus comprises a rotational speed detection module; wherein
 the rotational speed detection module is configured to: when the rotor of the motor rotates, detect a rotational speed of the rotor at the current moment by using the Hall sensor; 
 the target torque coefficient determining unit is specifically configured to determine the target torque coefficient by using a first torque coefficient model according to the back electromotive force detected by the back electromotive force detection module and the rotational speed detected by the rotational speed detection module; wherein 
 the first torque coefficient model is 
 
       
         
           
             
               
                 
                   K 
                   T 
                 
                 = 
                 
                   
                     3 
                     2 
                   
                   × 
                   
                     E 
                     n 
                   
                   × 
                   
                     60 
                     
                       2 
                       ⁢ 
                       π 
                     
                   
                 
               
               , 
             
           
         
       
       wherein K T  is the target torque coefficient, E is a peak value of the back electromotive force, and n is the rotational speed of the rotor. 
     
     
       8. The motor driving apparatus according to  claim 7 , wherein the relational model for a phase current and a torque coefficient is 
       
         
           
             
               
                 
                   K 
                   T 
                   ′ 
                 
                 = 
                 
                   T 
                   I 
                 
               
               , 
             
           
         
       
       K T   ′  is the current torque coefficient, T is a predetected or calculated load torque, and I is a peak value of the phase current of the motor. 
     
     
       9. The motor driving apparatus according to  claim 8 , wherein the adjustment module further comprises a first determining unit and an acting unit; wherein
 the first determining unit is configured to determine whether the current torque coefficient and the target torque coefficient meet a torque coefficient error model, wherein the torque coefficient error model is 
 
       
         
           
             
               
                 | 
                 
                   
                     
                       K 
                       T 
                       ′ 
                     
                     - 
                     
                       K 
                       T 
                     
                   
                   
                     K 
                     T 
                   
                 
                 | 
                 
                   ≤ 
                   ɛ 
                 
               
               , 
             
           
         
       
       and ε is determined according to the first error range;
 the acting unit is configured to: if the current torque coefficient and the target torque coefficient meet the torque coefficient error model, use the current angle as the adjustment angle; and 
 the compensation angle determining unit is specifically configured to: if the current torque coefficient and the target torque coefficient do not meet the torque coefficient error model, determine the compensation angle according to the rotor angle compensation model. 
 
     
     
       10. A motor-based electric appliance, wherein the electric appliance comprises the motor and the motor driving apparatus according to  claim 7 . 
     
     
       11. The motor driving apparatus according to  claim 6 , wherein the compensation angle determining unit specifically comprises a second determining unit, a first compensation angle determining unit, and a second compensation angle determining unit; wherein
 the second determining unit is configured to determine whether a difference between the current torque coefficient and the target torque coefficient is within a second error range; 
 the first compensation angle determining unit is configured to: if the difference is outside the second error range, determine the compensation angle θ i  by using a first rotor angle compensation model, wherein the first rotor angle compensation model is θ i =2 i ×Δ, θ i  is an angle for the i th  compensation, i is greater than 1, and Δ is a unit angle; and 
 the second compensation angle determining unit is configured to: if the difference is within the second error range, determine the compensation angle θ i  by using a second rotor angle compensation model, wherein the second rotor angle compensation model is θ i =1/2×(|θ i-1 −θ i-2 |), θ i  is an angle for the i th  compensation, θ i-1  is an angle for the (i−1) th  compensation, and θ i-2  is an angle for the (i−2) th  compensation.